The present invention relates to a control apparatus for game machines, and more particularly to a control apparatus for coin-operated game machines such as slot machines into which coins or tokens (which are hereinafter referred to as "coins" for simplicity) are inserted for playing a game.
In casinos or game centers, having a large number of coin-operated game machines, it is known to provide a control system in which the game machines are divided into groups in each of which a special favor is enjoyed when a specific win is accomplished. For example, slot machines are divided into groups each of which has about 20 to 30 slot machines and particular hits such as jackpots (a jackpot is the largest hit of a slot machine game and is hereinafter referred to as a "JP") are processed for each group by a so-called progressive method.
In this progressive JP-process, a master control unit controls a plurality of slot machines, for example, 30 slot machines as one group and accumulates a predetermined percentage of an amount of money corresponding to the number of coins inserted into each slot machine of the group. When a JP occurs in one of the slot machines, the master control unit orders the slot machine to pay out coins corresponding in number of the accumulated money. As the accumulated money to be paid out is indicated by an indicator, the players' enjoyment is enhanced by the hope of hitting a JP which pays a large amount of money increasing as time passes.
In a conventional JP-process by the progressive method, the money accumulated by the master control unit is cleared to zero and the indicator correspondingly indicates zero after a JP occurs. Subsequent players lose interest in hitting such a small JP.
To solve this problem, in another progressive JP-process, a minimum amount of money is set up as a reserve and the accumulation starts from that minimum amount of money. A player hitting a JP can receive prize money in an amount greater than the minimum amount of money even when the JP occurs soon after the last occurrence of a JP. However, the minimum amount of money cannot be set too high, lest it distort pay-out ratio. Accordingly, the prize for a JP which occurs soon after the last JP is rather small.